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Telesystems Conference, 1993. 'Commercial Applications and Dual-Use Technology', Conference Proceedings., National

Date 16-17 June 1993

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Displaying Results 1 - 25 of 45
  • Proceedings of 1993 IEEE National Telesystems Conference

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    Freely Available from IEEE
  • On adaptive arrays in mobile communication

    Page(s): 55 - 58
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    The author studies the use of adaptive arrays in mobile communication for increasing channel capacity as well as reducing co-channel interference. Antenna arrays may be used at the base station and/or at the mobile unit. A mathematical model for the received signal is presented and discussed in the context of frequency division multiple access (FDMA), time division multiple access (TDMA) and code division multiple access (CDMA). It is shown from the carrier-to-interference and noise ratio (CINR) for a single- and an array-antenna that the latter results in reduced co-channel interference View full abstract»

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  • Fully remote controlled telemetry tracking antenna system

    Page(s): 253 - 262
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    The authors describe a high-performance telemetry receiving antenna tracking system which utilizes unique software to allow full remote control of the tracking antenna, two telemetry receivers, and a diversity combiner. Features include a modular pedestal design, electronically scanned tracking feed (ESCAN), mouse-driven software which uses full-screen representations of selected components, and a joystick linked through a serial interface to the control computer to allow slewing of the antenna axes. This state-of-the-art system allows operation from the front panel of the controlled devices and over an extended distance via fiber-optic bus extenders View full abstract»

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  • Velocity matched filtering/coherent integration of ultrawideband pulse trains

    Page(s): 191 - 195
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    The development of optically activated semiconductor switches has advanced to the point where they are ready for implementation in radar systems. Extended detection range is possible when the switch is operated at high pulse repetition frequencies combined with integration of multiple pulse returns. Coherent integration of the returns from moving targets is described, based on real signal processing instead of analytic signal derivation, with velocity as the observable. The performance of this approach is quantified View full abstract»

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  • The search and rescue communications channel-past, present and future

    Page(s): 131 - 138
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    From a macroscopic viewpoint, the underlying concept for search and rescue (SAR) involving radio beacons is a communications channel. The communications channel should establish a two-way link by providing confirmation of the message received. The author outlines the different aspects of the SAR communications channel from its very beginnings to the current COSPAS-SARSAT satellite system, and he attempts to predict its evolution into the next century. The first SAR communications channel was instituted with legislation mandating the installation of 121.5-MHz emergency locator transmitters (ELTs) or crash position indicators (CPIs) on all aircraft. Improvements in the communications channel through faster detection of the ELT and better location accuracy were made. The world's first prototype local user terminal (LUT) was introduced in the late 1970s. This is a satellite receiving station designed explicitly for the SAR communications channel. The LUT itself now detects and locates the beacon transmitter. A global communications network, specifically for SAR data, should eventually emerge View full abstract»

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  • Transportable orbital tracking, telemetry and command system

    Page(s): 241 - 249
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    NASA/Goddard Space Flight Center has implemented an automated ground-based telemetry, command, and Doppler system. Its function is to support the low-earth-orbiting satellite and sounding rocket programs. This fully transportable system can be configured with the capability to provide unmanned satellite support for seven days or operator augmented automated sounding rocket launch and tracking support. An extensive overview of the evolutionary status and functional capabilities of such systems is provided View full abstract»

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  • Influence of various PCS spectrum allocation schemes on the ability to share spectrum with incumbent microwave users in the 1850-1990 MHz band

    Page(s): 45 - 53
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    The success of personal communication services (PCS) rests in the ability to share spectrum with incumbent microwave users in the 1850-1990-MHz band. Spectrum allocations from 20 MHz to 40 MHz per PCS licensee are being considered by the FCC. While it may be possible to make some spectrum available by negotiating relocation agreements with certain of the microwave users in a given MSA, local government users may remain co-primary operators in the band indefinitely. The results of computer modeling indicate that these remaining local government microwave systems may greatly inhibit and even prevent the deployment of a PCS system in a given band depending upon the spectrum allocation scheme. The authors explore the 20-MHz, 30-MHz, and 40-MHz PCS allocation schemes and compare the amounts of available spectrum under each allocation scheme. In addition, they examine these spectrum availability amounts considering the influence of local government microwave paths. The conclusion is that the larger spectrum allocation schemes will greatly facilitate the deployment of interference-free PCS systems View full abstract»

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  • A comparative study of JPEG and residual VQ compression of radar imagery

    Page(s): 203 - 207
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    The Joint Photographic Expert Group (JPEG) compression standard and a type of vector quantization called residual vector quantization (RVQ) are evaluated for the real-time compression of precision approach radar (PAR) video data. Experimental results obtained from simulated PAR imagery are presented which allow a performance and complexity comparison of the two compression methods. For low to moderate compression ratios, JPEG is the preferable solution because of its good performance and relatively low complexity. For higher compression ratios, JPEG gives unacceptable image quality and RVQ is the preferred solution View full abstract»

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  • Advanced RF cards for fare collection

    Page(s): 31 - 35
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    Transit fare collection systems are discussed. The public transit industry has shown a strong interest in the value that smart cards can bring to the fare collection process. At the same time, the toll collection industry has migrated to radio frequency (RF) methods for advanced electronic toll collection and traffic management (ETTM) systems. The ideal solution to the fare collection problem may be to combine the salient features of smart cards with RF data communications between the fare card and the transportation system. The resulting system would have all of the desirable features of hands-free fare collection combined with the data management aspects of smart cards. The authors discuss the conceptual framework, the development progress, and the implementation schedule for the early tests of a hands-free RF smart card fare collection system. Cost goals and performance targets are also presented View full abstract»

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  • The RADARSAT remote sensing ground station for McMurdo station, Antarctica

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    Summary form only given. Under a memorandum of agreement with the Canadian Space Agency and NOAA, NASA has agreed to construct a remote sensing station and deploy it at McMurdo Base in Antarctica. The station is designed to receive the downlinked data from RADARSAT and to provide for future remote sensing applications on the Antarctica continent. The system, which was designed to meet the special requirements of this mission, incorporates numerous advancements in the state of the art. The design incorporates features that allow the system to be deployed in the short Antarctica working season and to operate in the extremely harsh Austral winter environment. In this environment, the system must operate autonomously at a site removed by almost two miles from the inhabited base. The only links for system control and data are via a dozen optical fiber cables. The authors discuss the current and potential requirements which drove the design and provide a description of the system which is currently under construction View full abstract»

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  • Receiver frequency resolution for range resolution in homodyne FMCW radar

    Page(s): 169 - 173
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    The author presents an analysis and simulation results relating the range resolution to the receiver frequency resolution in a linear frequency modulated, continuous wave, (FMCW) homodyne radar. He considers the relationship between range resolution and receiver frequency resolution for systems that use the fast Fourier transform (FFT) to form multiple frequency and range bins. A millimeter wave (MMW) seeker application is used as an example View full abstract»

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  • A large W-band slotted waveguide array

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    Summary form only given. Slotted arrays at millimeter-wave frequencies play an important role in commercial applications such as collision radars and synthetic vision systems. The authors describe the design, fabrication and testing of a 3-ft-long slotted waveguide array having 600 edge wall slots. The design represents a low-loss technique for achieving a high-resolution pattern and uses a standard WR-10 copper waveguide for minimal ohmic loss. The slot angles are varied to radiate a nearly uniform illumination with minimal power absorbed in the load. The arrays are embedded in a fared waveguide section to enhance the discrimination in the direction orthogonal to the waveguide axis and to increase the array gain. The arrays have been tested in the laboratory environment for return loss and insertion loss. They have also have been tested on the EMS planar near-field facility for near-field amplitude and phase and the resulting far-field patterns View full abstract»

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  • Prospects for international TVRO growth

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    Summary form only given, as follows. With the introduction at the end of 1993 of the high EIRP INTELSAT VII/VIII-A satellites, the INTELSAT network is about to enter a new phase of dramatically increased capability. Voice, data and video services will become practical on global scale to much smaller ground terminals than ever before. A similar situation occurred in the United States in the late 1970s and, if the experience in the US is a reliable guide, this new capability will manifest itself as a major increase in the number of users of the INTELSAT network and the creation of new or greatly expanded markets. The author traces the development of these services in the US and estimates the potential for growth in other countries View full abstract»

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  • MMW technology for enhanced situation awareness/enhanced vision systems

    Page(s): 97 - 99
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    Millimeter wave (MMW) radar systems are now demonstrating the ability to image airport environments in fog. The authors discuss the use of MMW radar technology to provide pilots with enhanced vision and enhanced situation awareness. One of the first steps in providing an autonomous aircraft is the Enhanced Vision System (EVS). This system consists of a heads-up display (HUD) and an imaging MMW radar that provides the pilot with runway imagery on the HUD. Hughes Aircraft Co. has developed a MMW radar designed specifically for the EVS application. This radar was designed to provide the range, resolution, accuracy, update rate, and safety monitoring functions required to meet the demanding Category III FAA certification requirements. The Hughes MMW radar comprises three subsystems: the processor, transceiver and antenna. The radar is currently undergoing testing. To test the radar's ability to compensate for aircraft motion and provide real-time imagery, a dynamic platform was used to simulate aircraft motion View full abstract»

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  • ATMS 2000: hybrid automation or a lights out traffic management center?

    Page(s): 37 - 42
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    Because of rapid advances in information and automation technology, traffic management center (TMC) design is in a period of rapid evolution. Larger numbers of more capable traffic and environmental sensors are being fielded. Data fusion and information processing equipment are beginning to exploit this new quantity and quality of information. Automation of routine tasks may help to moderate peaks in operator workload, and new information channels may provide more opportunities for informing the driver. Selecting the appropriate level of automation for the TMC is a major challenge. Experience with manufacturing and process control industries suggests that the lights out factory, in which there are no humans in the control loops, may become a reality; visionaries are beginning to discuss an analogous lights out TMC. The transportation system TMC, however, must control variation and deviation from the norm in many more dimensions than a factory does. In the near term, then, the TMC design philosophy should support user-centered hybrid automation View full abstract»

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  • Smart card applications in integrated transit fare, parking fee and automated toll payment systems-the MAPS concept

    Page(s): 21 - 25
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    The concept for a multimodal access and payment system (MAPS) promising to provide a common mechanism for the payment of transit fares, parking fees, tolls and other transportation-related items is described. MAPS will focus on the use of smart card technology and smart cards interfaced to RF transponders on vehicles to relieve the traffic congestion and air pollution problems which are becoming increasingly severe in urban areas. MAPS smart cards will maintain logs of the actual transportation modes used on employee journeys to and from work. Trips made as passengers in ride share or high occupancy vehicles will also be recorded on the smart cards. These logs can be used for the purposes of measuring the effectiveness of corporate traffic congestion and air pollution mitigation programs and in certifying compliance with regulations in these areas. Profile information on primary and alternate travel itineraries and modes will be maintained in the smart cards. This information can be used in future extensions of MAPS to supply users with traffic and transit information, updated schedules and alternate routing specific to their trip View full abstract»

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  • Precision approach radar (PAR)-remote operation feasibility study

    Page(s): 197 - 201
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    It has been determined that it is feasible to have remote displays and controls of the AN/FPN-63 precision approach radar (PAR) over a narrow bandwidth communication link. The system design maintains the functional requirements of the current radar as required by the applicable air traffic control documents. After processing, one or two dedicated 56 kb/s telephone lines are able to transmit the 4-MHz video and control signals with minimal loss of radar image quality View full abstract»

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  • Genesis: personal traveler information system

    Page(s): 27 - 30
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    Construction of new freeways is coming to an end due to right-of-way, environmental, and construction cost problems. Efforts have, instead, been placed on increasing the efficiency of existing facilities through the use of current and evolving technologies. A major example of these efforts is the intelligent vehicle-highway system (IVHS). The IVHS program developed for the state of Minnesota is entitled GUIDESTAR. Under this program, a series of projects have been initiated, one of which is called Genesis. The goal of the Genesis project is to operationally test and evaluate the effectiveness of personal communications devices (PCDs) in providing real-time traveler information. The authors describe the Genesis concept, its various elements, its current progress, and the proposed testing activities View full abstract»

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  • On the processing gain and pulse compression ratio of frequency hopping spread spectrum waveforms

    Page(s): 215 - 219
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    The authors consider the pulse compression ratio and processing gain of frequency hopping spread spectrum waveforms. The importance of the frequency separation-subpulse width product is studied. Typical autocorrelation functions for coherent and noncoherent frequency hopping systems are given View full abstract»

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  • Synthetic vision/enhanced vision system implementation

    Page(s): 91 - 95
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    There is an emerging requirement within the world's air transport network to improve safety and increase productivity by enabling aircraft to perform visual flight operations under low-visibility weather conditions. Currently, the commercial aviation industry has centered its efforts at achieving this requirement around a millimeter-wave imaging radar and/or imaging infrared (IR) sensor, a Global Positioning System (GPS)-aided inertial navigation system, and a heads-up-display (HUD) to enable a minimum set of low-visibility functions. Honeywell has flight tested a 35-GHz radar as part of the Synthetic Vision System Technology Demonstration (SVSTD) program, and the authors describe the system implementation, signal processing, and resulting flight test results. The focus is on the terminal area navigation and landing problem in adverse weather using existing avionics with appropriate sensor and navigation upgrades View full abstract»

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  • Application of aerostat radars to drug interdiction

    Page(s): 181 - 183
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    The application of aerostat radars for the purpose of detecting and tracking low flying aircraft and small ships used for drug smuggling is an example of an application of technology to nonmilitary purposes. Sophisticated coherent radars that include moving target indication (MTI) and pulse compression processing to achieve the target extraction from clutter have been adapted from military coherent radars. The Georgia Tech Research Institute (GTRI) is reviewing the design of the aerostat radar and is tasked to perform field test measurements to verify the achievement of the clutter rejection ratios. GTRI has developed a special calibrated Doppler producing target, as well as a large stationary target, for testing MTI performance of the aerostat radars. One of the factors critical in evaluating the MTI performance is that of accounting for the effects of multipath interference on the measurements. GTRI is planning to use a refined measurement method with a field probe to characterize the effects of multipath interference and insert the field probe results into a GTRI model to correct for the effects of multipath interference View full abstract»

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  • GPS relative navigation for automatic spacecraft rendezvous and capture

    Page(s): 155 - 168
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    NASA, in collaboration with the European Space Agency (ESA), is planning a space experiment involving the space shuttle and two spacecraft in low Earth orbit to demonstrate autonomous rendezvous and capture (AR&C). The results of the preliminary design of a global positioning system (GPS)-based relative navigation filter for AR&C are presented. The domain of operation of the GPS relative navigation filter considered here is from a 2-km separation to 100-m proximity operation. The authors describe the navigation filter algorithm, the truth models employed in the evaluation of filter performance, and the results of the performance evaluation. Relative navigation filter performance results obtained by simulation show a relative position accuracy of about 2 m (1-σ) in the presence of selective availability (SA) errors. In contrast, the performance of the more traditional state vector difference (SVD) method is shown to fluctuate in the 10-20-m range. The results obtained demonstrate that the filter developed provides higher relative navigation accuracy and greater immunity to transients than the SVD approach View full abstract»

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  • Pseudo windowing for synthetic sampled aperture radar target detection

    Page(s): 185 - 189
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    The authors introduce a significant modification to the coherent integration algorithm of synthetic sampled aperture radar (SSAMAR) processing to achieve Hamming-like or cosine to the fourth-like tapering. Only pseudo Hamming or cosine to the fourth tapering is possible because the coefficients of the coherently integrated SSAMAR returns are integers. In other words, the coefficients of the returns will approximate the desired window, by following its general shape. Examples through computer simulation are used to illustrate the new algorithm. The advantages are side-lobe attenuation of 40 to 48 dB, while maintaining the main beam characteristics, and a significant improvement of the SNR View full abstract»

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  • FLAPS reflector antennas

    Page(s): 233 - 238
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    A flat parabolic surface (FLAPS) reflector is a thin (planar or conformal) surface consisting of an array of elements, each functioning as a radiator and phase shifter. Unlike a conventional planar array, however, the elements on the FLAPS surface are spatially fed using a feed assembly, as in a conventional reflector system. This results in an antenna technology that offers the advantages of both planar arrays and reflector systems. Additionally, FLAPS technology offers packaging and deployment ease and is suitable for a variety of manufacturing processes and procedures using low-cost materials. Other features, such as polarization control, large apertures with low windloading, and low-cost electronic beam switching, are also possible. Initially developed for defense microwave and millimeter-wave radar applications, FLAPS antennas are now being developed and fielded in many defense as well as commercial radar and communications systems View full abstract»

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  • High resolution MMW seeker fuse processing

    Page(s): 175 - 179
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    The authors describe a new signal processing technique for phased arrays that can be used in near-field target imaging. This processing technique is useful to millimeter wave seekers employing planar phased arrays as a new approach to performing warhead fusing. The array operation and signal processing are similar to synthetic sampled aperture radar (SSAMAR). Through a coherent integration of all echoes, a two-dimensional information sequence is synthesized. The array pattern is computed as the amplitude spectrum of the information sequence (which is twice the size of the actual array). Thus, the angular resolution is doubled, and the sidelobes are significantly attenuated. A new mathematical model for the round trip delay based on a Taylor series expansion of the phase is also introduced. This model allows correction for the nonlinearity associated with two-array phase. It follows that near field target tracking (with a focused image) is possible through correction for the dominant second-order phase terms. Examples through computer simulation are used to validate and verify the theory View full abstract»

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